Arguing With A Dang Computer

I’m a reasonably good automobile mechanic and a very good computer programmer. Put the two together, however, and I got stymied by our 2003 Dodge van. Here’s the backstory.

I started learning to be a mechanic on the remote cattle ranch where I grew up. If you live at the far end of nowhere, you can’t call a mechanic or a plumber or an electrician. So you have to learn to be all of those. As a result, by the time I got out of high school, I could fix a lot of stuff. I also had a totally unjustified, unsupported, and unrealistic opinion that I could fix anything … ha.

I only got good at mechanics, however, when three friends and I opened up the People’s Garage of Santa Cruz in 1968. I was twenty-one, the other guys about the same age. The master mechanic among us four was Jeffrey. He was one of those guys who seem to have been born with a wrench in his hand. Can’t tell you how much I learned from him about auto mechanics in general and infernal combustion engines in particular. He really could fix anything.

The most important thing I learned from Jeffrey was that when you get into disputing the toss with a nominally inanimate machine, you have to be convinced that you will win. For example, Jeffrey taught me that if a gasoline engine has spark, compression, air, and fuel, it has to start. No question, no debate, it would start for Jeffrey. He knew no matter what an engine threw at him, he would always be able to get that engine running … and he always did.

So I took up that point of view, and it has served me well in a lifetime in which I can’t count the amount of internal combustion engine surgeries I’ve participated in.

And computers? Well, I first programmed a computer in 1963 … it used punch cards, and it took up a whole room. I was entranced by the process, and I have been writing programs ever since. When Tandy brought out the first “personal computer”, the TRS-80. I bought one. I wrote navigation programs for it and used it to navigate from Fiji to Tonga … however, that’s another story, and a rollicking good one to be sure, it’s the sequel to my sea tale about Modern Piracy … but it’s not this story.

And to return to this story, when IBM came out with the first IBM PC, I bought one. I drove it non-stop for a couple of years. Then Apple came out with the Mac. I bought one. I figured I’d use the Mac for graphics and the IBM for all the real work. But once I bought the Mac, I never used the IBM, and when the dust got a half-inch thick on the PC, I traded that poor computer for a piano and never looked back. Since then, among other jobs, I worked for a while running the service department for the only Apple Computer Dealer in Fiji … hey, someone’s got to do it, and the waves weren’t going to surf themselves …

So as a mechanic and a computer programmer, when I found out that our Dodge van didn’t pass the smog pretest, I figured hey, no problemo. I thought that because the issue, according to the paperwork, was that the van’s computer monitor for the catalyst wasn’t kicking in. I knew automobile engines, I knew computers, I could fix them both … and I knew absolutely nothing about automobile computers.

But hey, how hard could it be to get an automobile computer monitor to kick in?

… little did I know …

Now, all US cars since 1996, and all European cars since 2001, have an onboard computer called the “OBD” system. The acronym refers to the On Board Diagnostics computer. These days it’s mostly the second version, OBDII. The OBDII system is what watches the automotive monitors and turns on the infinitely irritating “Check Engine” light …

Now, my only good fortune in all of this was that I got a “Check Engine” light a few months ago. Sounds like bad fortune, but it wasn’t, because after I said the requisite number of bad words, I figured I should check the engine out myself. So I went and bought an OBDII reader. The one I bought is called the “BlueDriver”, ninety-nine bucks plus tax from Amazon, and it is slick. It’s just a small Bluetooth-equipped unit that plugs directly into the OBD port underneath the dashboard near the steering column.


It hooks up wirelessly with an app for my iPhone. And it is amazing what the BlueDriver can tell me about any car I plug it into. Incoming air temperature, RPM, speed, atmospheric pressure, there are monitors throughout the car that the computer uses to adjust the fuel mixture and watch for malfunctions. Man, I could have used this when I was part-owner of the People’s Garage …

In any case, I found out that the Check Engine light was telling me that there was a slight leak at the O-ring gasket at the gas cap … who knew that the car watched my gas cap O-ring?

I sure didn’t know … but I fixed it on the spot by using some spit to clean off the O-ring and I got it working again. Like I said … cattle ranch trained, use what’s at hand.

In the case of our Dodge van, my BlueDriver was able to check out the status of all of the onboard monitors. And it agreed with the guys at the smog shop. It said that the catalyst monitor wasn’t integrating into the OBD system. This kinda made sense because we’d replaced the catalyst a few months before. Upon asking the smog guy, he said that if they had changed the catalyst we just needed to drive the car for a hundred miles or so, and the monitor would kick it.

Since we’d put about three hundred miles on the vehicle since replacing the catalyst, driving another hundred miles didn’t seem like it would work. So we went back to the muffler shop where they’d changed the catalytic converter. The owner said, just drive for an hour at 55 on the freeway and the monitor will long in … hmmm. We’d already done more freeway miles than that. At this point, my mechanic’s urban legend detector was starting to go off. We called another shop. They also said put another hundred miles on it, but turn on the air conditioner and the rear defroster. Whaa?

The muffler guy recommended another mechanic. We went to him. He said the thing to do was to disconnect all of the monitors from the OBD and start over … sounded drastic, but I was out of ideas, so we said OK, and he disconnected them all. Then, he said, start your car, let it idle with the air conditioner on, and drive it on the freeway for a couple of hours. Hmmm again …

I went home and thought about all of this. None of it made sense. Why not just have monitors that logged in when they were installed? What was the driving about? Clearly, further research was in order.

So I went on the web and found what was claimed to be a “universal driving cycle” that was supposed to integrate all of the monitors and kick them back into action. It was necessary because the monitors need to know what the normal conditions for your particular car are. The claim was that “A complete universal driving cycle should perform diagnostics on all systems. A complete driving cycle can be done in under fifteen minutes.” Sounded good. It went like this:

Park the car overnight. In the morning, start the car up and let it idle for five minutes so it will be in “closed loop”, whatever that meant.

Then speed up gradually to 55 mph and hold it there for four minutes.

Finally, coast to a stop.

Sounded like voodoo to me. Plus, I live at the end of a twisty road in a forest. No way I could get in my car in the morning and immediately accelerate to 55. So I did the best I could. I started, idled, drove to where I could do 55, went through the routine … nothing. There were four monitors not logging in—the monitors for oxygen, for the oxygen heater, for evaporation, and for the catalyst. They were all still giving errors. So I went through the driving cycle again, but without the five minutes idle … and the BlueReader reported that the oxygen monitor came online.

Encouraged, I went through the whole routine again, up to 55 again, coast to a stop. Nothing. No more monitors coming to their senses. Go figure.

Next day, after more research on the web, I found instructions for the universal driving cycle specific to General Motors vehicles including Dodges. Here’s that charming bit of instructions:

To perform an OBDII Driving cycle do the following:

Cold Start. In order to be classified as a cold start, the engine coolant temperature must be below 50°C (122°F) and within 6°C (11°F) of the ambient air temperature at startup. Do not leave the key on prior to the cold start or the heated oxygen monitor diagnostic may not run.

Idle. The engine must be run for two and a half minutes with the air conditioner on and rear defroster on. The more electrical load you can apply the better. This will test the O2 heater, Passive Air, Purge “No Flow”, Misfire and if closed loop is achieved, Fuel Trim.

Accelerate. Turn off the air conditioner and all the other loads and apply half throttle until 88km/hr (55mph) is reached. During this time the Misfire, Fuel Trim, and Purge Flow diagnostics will be performed.

Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for 3 minutes. During this time the O2 response, air Intrusive, EGR, Purge, Misfire, and Fuel Trim diagnostics will be performed.

Decelerate. Let off the accelerator pedal. Do not shift, touch the brake or clutch. It is important to let the vehicle coast along gradually slowing down to 32km/hr (20 mph). During this time the EGR, Purge and Fuel Trim diagnostics will be performed.

Accelerate. Accelerate at 3/4 throttle until 88-96 km/hr (55-60mph). This will perform the same diagnostics as in step 3.

Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for five minutes. During this time, in addition to the diagnostics performed in step 4, the catalyst monitor diagnostics will be performed. If the catalyst is marginal or the battery has been disconnected, it may take 5 complete driving cycles to determine the state of the catalyst.

Decelerate. This will perform the same diagnostics as in step 5. Again, don’t press the clutch or brakes or shift gears.

Zowie, sez I …

So I did the best I could to emulate their special cycle, and after two tries, the oxygen heater monitor woke up and logged in. Great, I thought, this is working, this won’t be a problem.

But three more tries did nothing for the evaporation monitor or the catalyst monitor … grrr. So it was back to the web, where to my surprise I found instructions specific to Dodge catalyst monitors, as follows:

The catalytic converter monitor will not run unless the Check Engine light is off, no pending codes are present, the fuel level is between 15 and 85 percent full, and the coolant temperature is above 70 degrees F. If these conditions have been met, the engine must have run at least 90 seconds, and the engine speed must be between 1,350 and 1,900 rpm. Idle vehicle for five minutes (to reach closed loop operation), then drive at a steady speed between 30 and 45 mph for two minutes.

By this point I was getting frustrated by not knowing what “closed loop operation” was. After more research, I found out that when modern cars start, the fuel-air mixture is determined by factory settings. This is called “open loop” since the car’s monitors aren’t feeding information back to the computer. It’s just running on the hard-wired average numbers set at the factory.

But once the engine gets warmer, the monitors kick in and start sending information back to the computer, closing the loop. At that point the computer can fine-tune the fuel-air mixture based on real-world conditions. This is called “closed loop operation”, because the monitors are sending information back to the computer and thus “closing the loop”.

So … next day, after figuring out how to use my BlueDriver to verify that the car was actually in “closed loop operation”, it was back out on the highway, and to my surprise, after running that specific catalyst driving cycle for only four times, danged if the catalyst monitor didn’t kick in! Pure joy!

Well, not quite pure. That left only the evaporation monitor. The instructions said the drive cycle for the evaporation monitor was the same as for the catalyst monitor, so I ran that drive cycle about six more times … no joy. Head home.

So it’s back to the web, where I find that the evaporation drive cycle instructions part I’d already found were only the first part of the drive cycle for the evaporation monitor … there’s also a second part, viz:

Evaporation: There are two-parts to this test. The first part runs after idling for five minutes, then driving at 30 to 45 mph for two minutes (fuel tank must be half to 85 percent full).

The second part runs after the vehicle has sat for 8 or more hours (cold soak) without being driven. Start the engine and idle for four minutes, then drive in stop-and-go traffic for five minutes using smooth accelerations and decelerations. Stop and idle for 4 minutes. The EVAP monitor should be complete.

I’d only done the first half … and besides, by the time I’d fixed the catalyst monitor and gotten to the evaporation monitor, I had less than half a tank. So, drive to the city, get gas, do some real stop-and-go city driving, come home, park the car. I was hoping the evaporation monitor would come on from that city-type driving, plus the extra miles on the highway … no joy.

Next morning, start and idle. Now, we live way out of town, no stop-and-go traffic, but that’s no problem. I just drove the back roads for five minutes, stopping every thirty seconds or so at imaginary stop lights. Then I idled the engine for four minutes just as the instructions said, and used the BlueDriver to check the evaporation monitor …


However, after working with Jeffrey for a couple of years at People’s Garage, I’ve got Jeffrey’s mindset—when I start fixing a car, that sucker is gonna get fixed, no options, no question.

So I sighed, and I must confess that I said some impertinent and anatomically improbable things about the designers of the Dodge van in general and about OBDII programmers in specific … and I went out to do yet another cycle of stop-and-go driving.

And wonder of wonders, halfway through that drive cycle, the tenth or twelfth drive cycle I’d done over four days, the evaporation monitor finally decided to join the party.

As you might imagine, we took the vehicle to the smog shop immediately, before any of the tiny monitors could change their tiny minds, and it passed the smog test with flying colors.

Is there a moral in all of this? I’d say the moral is the old phrase from the I Ching, the one that says “Perseverance Furthers”. Like everything else in this life, fixing cars is a matter of intention.

Remember, when I started this I knew nothing about car computers. I’d used my BlueDriver once, for a “Check Engine” light diagnosis. I’d never heard of a “drive cycle”. I didn’t know what “closed loop” or an “open loop” was. I didn’t know my car even had a catalytic monitor, nor that there was a specific drive cycle to make the monitor come to life.

All I had was my intention, my unbreakable determination to mess with that vehicle and not stop messing with it until it finally gave up and came to the party. If the first driving cycle doesn’t do it, repeat the same cycle four more times, that’s what it took for our van. Intention is magic. Focus it, stay with it, and there are few limits to what any of us can achieve.

Best wishes to all, offered in my firm and unwavering conviction that we can all realize our dreams,


60 thoughts on “Arguing With A Dang Computer

  1. I was raised the same way.
    Still on the farm, own it now.
    Today I argue with a Toyota fork lift.
    It will start. No other option.
    Anything I cannot repair is almost always scrap, which justifies buying something new. Also explains why all our gear is so old!


  2. When I went to GM school (Delta College) in Bay City, Michigan, we were taught to always clear the codes before retesting. This was accomplished by removing the negative battery cable for 20 to 30 seconds. This reboots the computer/clears the codes/fixes odd glitches. This was in the mid-80’s, I reckon it may not be true these days.


    • I acquired a 2000 Lexus RX300 a few months ago. It was a 50 mile drive home. On the way I pulled into a Tractor Supply to get horse feed. With feed in hand I returned to my drive home with about 20 miles to go. Out of the driveway and up a hill and WHAM! No acceleration. I crawled up the hill. I could get the RPM’s up but I was not going any faster. I thought the trans had failed. OMG! Some fast phone work told me that the knock sensors had put the engine into fail mode. What? For the last decade my only vehicle was a 2002 Silverado 1 ton diesel. I had no idea what was going on. Or what an OBDII was. I was about to find out.

      Like you, it was back and forth to the web, YouTube, consultations and hair pulling. I, too, purchased the BlueDriver and had to learn how to use it.
      Unlike you, I have no automotive experience other than changing a clutch in my 1954 Chevy convertible when I was 16 and the occasional alternator or fan belt. But being stubborn and a programmer^ and a horse trainer and a clinical psychologist and growing up on a dairy farm, I was confident that I could find the problem and ‘fix’ it. If I couldn’t I could always do therapy on myself.

      Turns out the A/F sensors on both banks were not doing their jobs. Replacing those allowed me to drive the car as that fix brought it out of ‘limp’ mode. I found out the Fuel Trim mix was too rich and that put it in ‘limp’ mode to save the catalytic converters. Then there was cleaning of the MAF sensor. And replacing the spark plugs which highlights the downside to a transverse located engine. The plugs on bank 1 are up against the firewall and covered with the exhaust manifold, tubes and fuel lines etc. And I learned the definition of what a ‘seized’ spark plug was as I spent three days taking the one out of cylinder 5 hoping not to break it. Yikes! There was the angst that plagued the whole affair. That I’d do something stupid or ignorant and break an item that it would cost a thousand dollars to repair. A broken spark plug qualifies.

      There’s an argument amongst automotive engineers, mechanics and spark plug sellers: To use anti-seize or not. I am definitely in the ‘use’ it school. Also, Liquid Wrench to get the plug loose. I put 6cc’s of it in the chamber where the spark plug sits and over three days moved a ratchet back and forth about two inches at a time until little by little I could do more than one pass left and right.
      When it came free at last the Liquid Wrench had so cleaned the threads that I didn’t need to use a ‘follower.’

      It was an intense two month learning period. Quite an adventure.

      By the way, I have a journal article by mathematician Christopher Essex [author of Taken by Storm: The Troubled Science, Policy, and Politics of Global Warming]. You may already have it but if not, I have it in PDF format and it points out some problems with the use of meteorological models being used to plot climate change. If you’d like it let me know how I can get it to you.

      ^I took Fortran at FSU in 1972. I absolutely hated it and thought if this is programming I want nothing to do with it. Punch the cards. Go to the window and hand in the cards. Come back the next day to find there was an unspecified error. Spend a day searching for misplaced or l ost comma. Ahhhhhhh! The DMV experience on steroids.
      Thank god for Foxpro. A fast data language in English instead of esoteric script that allowed one to solve problems instead of solve programming.


  3. Thanks for the report. Who knew?

    Many years ago, in Idaho, auto inspections involved checking to see if brake lights and turn signals worked; were headlights aimed as they should be, and did the wipers move**.
    Then in 1988 we moved to Washington State. They wanted to test the tail pile to get the car registered in WA.
    WA does not have auto inspections on a regular basis.
    WA does have taxes and fees.
    Whether or not our monitors monitor, our cycler cycles, or our catalyst catalyzes seems to be of no concern to State officials. Not quite true. The web site that covers this seems filled with “Go To” and “If Then” statements. There is a sense that they feel new autos work well and they have already “fee-ed and taxed” about as much as the citizens can bear.

    **Many years ago, in Montana, an elk jumped on the front of a friend’s truck. That severely damaged both truck and elk. The windshield was gone. A passing motorist stopped and shot the elk.
    The responding trooper saw two issues. #1: Who shot the elk within the highway right-of-way? [No one knew.] #2: Did the wipers move? [They did, despite having no glass to wipe.]
    So all was good, and everyone went home.


  4. …Glad you had a TRS80!…back with it hooked to the TV and a recorder hooked to it…Basic was a simple wonderful language ..Every variable was global!…it was fun…Then came QuickBasic and (spit) and worse…


      • …The old TRS 80 also encouraged programming rigor…Each part of my programs began at the same specific line number…no part was more than 20 lines long, because the TV could only display about 22 lines…in practice, the actual program was short, calling a mass of subroutines…Remember Basic variables were global…for example, a random number (line 1000) the range would be set as R1= and R2= (names being used in that section) ,the RND function called, and R3 would return the number, which was then converted back (variable=R3)…Then came C and C++ and the joy went away…

        …another thing youngsters forget is that the screen is a storage work (with a PC and BASIC) we were sent a file of xyz coordinates and data like temperature (from a [company secret] CFD program) (no easy 3D [free] visualization programs available then either)…solution was to do a coordinate transformation to select the view, then sort the data from furthest away to closest along the z viewing axis (this took forever [remember PC Basic had 64K memory available and the data was a 200k+ file] so the sort was alternating reading and writing between two data files on the hard disk [I did ask our IT guy if I could wear out a hard drive])…then each data point (xy position)was set pixel by pixel on the screen (3D is hard determining if something is behind something else)…the resolution of the screen is limited, so if a data point was in front, it overwrote what was behind it…then capture the screen–not quite 3D (no perspective) but close…


    • Our progression was: VIC-20 to Commodore 64 to IBM PC

      We looked at Tandy and Texas Instruments.
      Almost bought a TI-99/4 but that would have required a 2 hour trip. Luck on that, as the TI had many issues.
      Then the IBM PC came, and getting one only required a 1 hour trip.
      Later we hacked the innards to get color, and then added a disk drive ($500 ?).

      Liked by 1 person

  5. With a spousal unit who works in the automotive industry I can totally relate to your frustration! At this point, the German auto makers are in a race to add CPUs to the seven to nine already linked together in the vehicle. Things are only going to get harder. I’m glad that enough people fought to get the right to maintain their vehicles, in particular farm equipment. Without that win, self-maintenance would have been nearly impossible to do.


    • Soon your car will collude with your washing machine and your smart phone. You will be totally outsmarted.

      The universal driving cycle is probably an invention of a particularly inept programmer, booted from One Infinite Loop.


  6. Wonderful, Willis!

    I chuckled all the way through your saga of sheer frustration with the opaque complexity of Chrysler maintenance. My late youngest brother had a Dodge Nitro that was his pride and joy – until it began to fail in a similar fashion to your van. Ian had no mechanical skills whatsoever and therefore relied on his garage. You fared better than the so-called professionals who failed repeatedly to resolve his problems.

    He was forced into the dreaded final solution. He sold the bloody thing and bought a Nissan X-Trail. The Japanese SUV hasn’t the romance of American iron, but doesn’t miss a beat. Ian’s widow still drives it.

    Keep the stories coming.



    • I have an X-Trail, and it’s been good… but at one point the air-inlet pipe had been disconnected and was just hanging loose. It ran just fine, until at the next service the mechanic noticed it and re-connected it…. well then the idle went a bit haywire… whenever we stopped the engine would rev high, then drop and almost stall the engine, rinse, repeat…. in order to stop this you had to use the accelerator to help it along. The mechanic claimed that to fix it required the replacement of the throttle body, or some such thing, which would cost several hundred dollars…. Well that didn’t sound right to me either, so I went home and did a google search. A few clicks later and I was trying the manual idle relearn sequence in the comfort of my own garage. Took two attempts to get the sequence right (key to on, wait, off, wait, press accelerator,etc, but after that it was fine…. of course a dealer could have done it by computer much easier. Just another fond memory of the interface between silicon and iron. 🙂


  7. I’m working to put a computer controlled engine in my old Scout (I’ve blown 5 stock diesels between the two trucks, so I need to do something different), but I am not really looking forward to having to deal with the computer in it.

    I’m going with the 2.8l cummins engine


  8. Wow. Some thoughts…

    ● Very educational! It will probably help me, someday. Thank you for writing it up.

    ● Some programmer(s) ought to be FIRED. Along with their managers. And their managers’ managers.

    ● Last time I checked, General Motor still hasn’t bought Dodge. That could change.

    ● I wonder how much fuel gets consumed, and pollution released, every year, by people doing these “drive cycles” … all in the name of fighting smog?

    ● I think the other mechanic, who “said the thing to do was to disconnect all of the monitors from the OBD and start over,” is not your friend.
    Did you unplug wires somewhere, or just disconnect the car battery for a few minutes?

    ● I wonder if the $99 BlueDriver for iOS is better than the 99¢ device for Android that I just ordered on eBay?


    • Thanks, Dave. I wrote it up in part in the hopes that someone could save a few steps.

      I don’t know if disconnecting all the monitors was a good idea or a bad idea. The good news was it forced me to look deeply into the question of driving cycles. In any case, he did it with his computer.

      Finally, not sure if the 99¢ device you got is better or worse than the BlueDriver. At a quick look it seems that they do most of the same things. However, the BlueDriver comes up first on this review site, which says:

      1. BlueDriver Bluetooth Professional OBDII Scan Tool
      The BlueDriver Bluetooth Professional OBDII Scan Tool for iPhone, iPad & Android by Lemur Vehicle Monitors is a professional OBD-II scanner that offers the best on-board diagnostics for your vehicle, trusted by many mechanics in North America. This Bluetooth scanner is designed to have all the capabilities found in expensive scan tools and leverages the benefits of your smartphone or tablet. You also don’t have to worry about the device compatibility because the BlueDriver Bluetooth Professional OBDII Scan Tool is officially licensed and certified for Apple and Android devices.

      But on the other hand, if you don’t need all that, saving $98 looks mighty tempting …

      Best to you,



  9. I had a mystery problem on a Dodge van. It was a ’77 B100 with the deuce and a quarter slant six, a very, very fine motor. It failed to start and I went through all sorts of components. The auto parts store was 5 or 6 blocks away and after about the 4th trip, the guy asked if I had checked the ballast resistor.

    What the heck was a ballast resistor?!? I’d never heard of them. They look like a little 2″ x 6″ block of ceramic with a couple of terminals at each end and cost a couple of bucks back then. (Just looked them up and they are all the way up to $5 now. Still a cheap part.)

    That was the problem and I learned to always carry a spare. The placement of the ballast resistor on the Dodge van made them susceptible to failure, so when the van didn’t start, that was the first thing replaced and it was usually the problem.

    Persistence pays. If there are never any problems to work out, you don’t learn anything.


    • True ballast resistor troubleshooting was “It starts and runs – until I let-go the key, then it stalls”.

      The starter circuit supplied full battery voltage to the ignition, all 14.4-or-so volts, for a hotter spark; so if you held the key over ( – which was MURDER on the starter – ) it would still run. But when you let-go the key, the run circuit feeds ignition voltage through the ballast resistor, which drops-back to 10-or-so volts; your points last longer; this was on ALL cars (AMC’s and GM’s had a 5-foot length of resistor wire in a main wiring loom instead of a ceramic chip – good luck replacing THAT!!!), and as computerised ignition came-out on Dodges ~1972, I never did figger-out why they still put ballast resistors in them after that. But they did – the three things you always carried on one of those was a ballast resistor, a new ignition module and (if you were up in the snow belt like me) some sandpaper – the control box grounded-on the fender under the bolts, and if it was rusty (which it always was), you had to sand-off the contact patches.

      Symptom of a dead ignition control module was, it wouldn’t start; then when you let-off the key, it would fire once – a single, tired-sounding “hrm”. Lost count how many times I diagnosed one of those by ear – thanks for the memories!


  10. I learned long ago that the machines can smell fear and take advantage of it. Must be Terminator genes lurking inside. Even very amateur mechanics like me have to approach them with attitude or the game is over before it starts.

    That gas cap O-ring trick got me once with a 2005 Honda Civic.


  11. I feel your pain, brah! We are fighting with a 2011 jeep compass with electrical issues. A component box with relays for various things is placed in the driver side wheel well. Ponder that. Electronics in a wheel well, where water and slush and crap resides. Relay for ignition/starter is the one closest to the wheel and that is also where all the wires enter the box. No cover or gasket. Relay wires corrode, relay corrodes, becomes clitchy then dies. Its a ghosty thing when it starts, plug it into diag computer and it cheerfully tells you nothing is wrong. That will be $178 please, come again! Youtube is where we found the fix for this. Sometimes the intrawebsthingy can be your friend!


    • Side note, I believe the OBD tool my mechanic uses can actuate some of those devices manually. His is connected to a laptop, but I am certain it wasn’t less than a hundred bucks for the software.


      • Thanks, ossqss. I don’t think that they can activate them manually. The reason that they have drive cycles is that the monitors need to measure the normal conditions for your particular car. The issue is not simply turning the monitors on. The issue is that the drive cycles actually calibrate the monitors, which can’t happen unless very specific driving conditions are met.




        • I went through something similar. I did a smog check with the BD unit to see what it would tell me about the catalytic converters. I would get results that said, ‘x test has not been completed.’ Looking into it I found the ‘drive cycle’ and conflicting info. I did manage to get it worked out and found I wasn’t turning the gas cap on tight enough. Got that taken care of and now have some ECU switch issues.


  12. Just cleared a similar problem with the wife’s 2012 Forester. She seldom drives it now, so the battery went dead, which death apparently upsets the computer, requiring that one do certain driving exercises to get everything working. The garage right away asked if the batt had gone dead, told me what to do. However, it never turned on the check engine light, just failed the emissions test. Three trips later, all’s well.

    Would like to send a story to you for your spare time. My email address attached.


  13. Willis, by now you should have registered how these systems are programmed –
    “why should they show you their codes when you are only going to try to find something wrong with them”

    Liked by 1 person

  14. I only got good at mechanics, however, when three friends and I opened up the People’s Garage of Santa Cruz in 1968. I was twenty-one, the other guys about the same age.

    Gosh, now you are bringing back memories.

    I maintain that the greatest instruction manual ever written was How to Keep Your Volkswagen Alive: A Manual of Step-by-Step Procedures for the Compleat Idiot by John Muir.

    Every technical writer should read it to learn the difference between describing and explaining.

    Liked by 1 person

    • Hey I used to be a technical writer. And our first rule was – make the doco look very technical. Otherwise, they’ll just get some semi-literate from the work experience students to produce it. And we’ll be out of a job.


    • The People’s Garage did a booming business in Volkswagen repairs … I could have used that book back then, but our customers could have used it even more. Can’t tell you how many VWs we fixed that had swallowed a valve lugging the engine going uphill …



      • I don’t know if you ever drove a Volkswagen in cold weather but they were notoriously cold and you could never get defrost. The common solution in the frigid north was to install a gas-heater. This was expensive and dangerous.

        I worked for a guy in Minneapolis who found a simple, inexpensive and elegant solution. He noticed that the air-cooled VW engine had an operating temperature of 250 degrees versus the water-cooled engine temp of 180-190. So where did all that heat go?

        The VW had no insulation and the heat exchangers hung out in the cold slipstream. So he insulated the exchangers, blew insulation into the frame around the heat ducts and put insulation under the floor mats. He sold it as a kit called “Snugbug”.

        And it worked!

        As a marketing tool, he used to drive around in his bus wearing a t-shirt when the temp dropped well below zero.

        The VW with rear-wheel/both wheel drive was an excellent car for driving in snow and once its heater was brought up to snuff, the car was a wonder.


  15. Willis, I’ve been a technical specialist for a car manufacturer for 20 years and used to teach OBD II to dealer technicians back in the 90’s (It became law in MY 1996)
    Believe me I feel your pain at trying to get the I/M flags to set. (monitors).
    I remember working on a car that had a evaporative emissions canister replace for an evap leak.
    I drove that car 4 consecutive days trying to replicate the driving cycle. The car had to be started cold and then driven specifically at certain speeds and times.
    Finally the I/M flag set on the fourth day.
    One of the reasons these tests are so difficult to pass is that the evaporative emissions requirement is that the fuel tank system must be able to detect a vapor leak of .020″
    .020″ is pinhole half the diameter of a paperclip, in a 18 gallon fuel tank.
    The computer uses data modeling of what the specific internal fuel tank pressure should be based on fuel level, temperature etc. The pressure sensor measures very tiny changes in pressure.
    I could go on and on, but I fear your eyes may gloss over.
    Glad you got it to pass.


    • Thanks, Pete. Man, the guys I talked to could have used some of your training. I was amazed that they basically knew nothing about driving cycles and their business is things like replacing catalytic converters …

      I was worried that the evap cycle would be screwed up because of the small leak that had given me the Check Engine light at the gas cap. So I took off the gas cap and put some lithium grease on the O-ring seal to get it to seriously cap off the tank … don’t know if it helps, but I figured it couldn’t hurt.

      Wecome to the blog,



    • Oh, yeah, forgot a couple of things.

      FSE Pete July 10, 2018 at 1:48 pm

      I could go on and on, but I fear your eyes may gloss over.

      Never gloss over. I get glassy-eyed sometimes, to be fair, but not about that stuff. I spent time alone at sea where my life depended on my intention and my abilities. I’m always happy to learn the details. Now I know, a hole half a paperclip size will be detected.

      Glad you got it to pass.

      Thanks. Intention.



  16. In things automotive , I have found that poor “ground” connections are frequent sources of problems . Especially on the instrument panel .
    Drives computers nuts …
    Also “Seafoam” less tha10 bucks at Wallyworld is highly useful . Biker friends swear by it . My old 77 F250 likes it too …


  17. Chassis grounds are the first thing I address with just about any electrical problem. They may look like new and clean but a disconnection, wire brushing, and re-connection has saved me untold grief. Previous untold grief lead me to start there.

    I picked up a ’99 Blazer that looked like new w/ 121k miles and fully loaded for 2 days work on a job. Locked in 4wd low, power window, and radio issues. Fooled with it for days then resorted to my learned default approach and cleaned the chassis grounds and all was well.

    Anyway, I wanted to eliminate the auto headlight while running and auto on at dusk. Well GM has the radio, turn signals, tail lights (one side), interior lights, and more crap tied together than the imagination can come up with so you can’t just turn the lights on when you want them on. Duh … I know when it’s dark. Days on the net and Blazer Forum and I found a remedy. Bend one tab on an under hood relay and install a 22k ohm resistor across the automatic light sensor that was in the speaker when the sensor was disconnected. Otherwise one of the tail lights would stop working. Go figure. GM wants your business at the dealership! It drove nice but it was a GM so no longer mine.

    The ’88 jeep is old but simple and reliable and low tax. By the way, I had to clean the chassis ground last week when the power window failed and wipers got slow. I started with the default approach … the wire brush!


    • I don’t have but a minute right now, but since there is a bunch of motor-heads and DIY minds that don’t want to pay $100/hr shop rates viewing, I want to toss in a good tip.

      If you are trouble shooting what “is or could be” an electrical issue and a a multi-meter or test light is not helping you, the get a “POWER PROBE”. I worked with Glen, a true electrical ‘wizard’ on RVs and motor homes, and spent a few months watching/helping him solve (or eliminate from possible causes) very difficult 12v electrical problems. I add one to my box of ‘mandatory’ gadgets/tools. It’s pricey at about $200-300 but it will pay for itself when you have an issue. The more you use it the more it pays for itself in time alone.

      The master set has very useful probes worth the extra $$$$. Find breaks, shorts, bad grounds, bad/weak connections, testing motors and relays, tracing circuits, etc. You must understand basic circuits to utilize it fully. You can only appreciate a tool like this when to see a ‘wizard’ at work with one!

      If you want more info look up an owners manual online.


      • They almost certainly have a “new car mode” in the software, which defaults the parameters, and suppresses the warnings, until the car has a few thousand miles on it.

        I don’t think brand new cars are emissions-tested, anyhow. I know that at least some States exempt them from inspection. Perhaps all States do:

        Smog Check Exemptions in Pennsylvania
        As mentioned, auto emissions testing in Pennsylvania is not a requirement for every vehicle. Certain smog certification exemptions are available if your vehicle: …
        ● Is a new vehicle with less than 5,000 miles. …

        Smog Check Exemptions in North Carolina
        Certain vehicles are exempt from emissions testing in NC, including vehicles registered in counties other than those listed above. …
        New motor vehicles that have never been titled before will receive a safety/tamper inspection for its first year of registration. During the second year of registration the full safety and emissions test will be required if the vehicle is registered in an emission county. Effective in 2015, vehicles within the three most recent model years that also have fewer than 70,000 miles may also qualify for an emission inspection exemption. …


  18. I once had occasion to replace the remote entry key fob for a 2005 Toyota Corolla. I bought a replacement on Ebay for about $30 and it came with the programming instructions (Toyota wanted a $100 programming charge after they’d already gotten over $100 for a new fob). Those instructions were less complicated than what you had to deal with, but still wacky — pretty much everything except tossing a pinch of salt over the left shoulder. I think it only took me three attempts before I got it all right and the fob worked.

    It seems that the “Myst” developers also do work for the car companies.

    And yeah, those bluetooth OBDII monitors are awesome.

    Liked by 1 person

  19. I hate it when the check engine light comes on in the middle of the desert miles from anything. I met a BMW owner once who just put electrical tape over the light. What I REALLY hate is that when the light comes on, it tells you nothing. “take it to the dealer”. It’s almost worth it to buy one of these units just in case. I am amazed that they are so cheap (although the cheapest ones may be pirate clones).
    See for example,

    The other thing that is amazing is that there is a standard. When automotive technical details are secret and proprietary and reverse engineering is banned by DCMA, I expected every manufacturer would have their own expensive diagnostic tools. According to Wikipedia, California’s CARB gets some credit for this.

    Beyond the weird procedures mentioned above, going to scary, see the Security Issues section of this last link!

    Liked by 1 person

    • Ha! I’m learning so much in this thread!

      From the Wikipedia article:

      Most of the clones are reporting [ELM327 v1.5], despite the fact that Elm Electronics does not have a version 1.5.

      Sure enough, the 99 cent unit that I ordered a few days ago claims to be version 1.5. 😏


      • There are two auto people on YouTube that are worth a lot of time spent with them. Chris Fix and Scotty Kilmer. Chris is a young guy with a boat load of knowledge in how to take care of autos from how to weld in a new floor in a sports car to how to clean a car that is filthy.
        Scotty is a life long mechanic who can fix anything and has a weird sense of humor. Both have taught me so much! Entertaining as well. They are two of the top people. There are more.


    • GM sued Sun Tools, Mac Tools, and others who developed a unit to read their codes back in the 1980’s (?). GM lost in court and the ultimate solution was a universal OBD port for all cars sold. Many who worked on cars and GM products put the word out against buying GM. They were at it in 1999 on the S-10 series as I know firsthand. I understand they modified the Vega engine because it was the low end product series and the engine last too many miles (over 100k which was good at the time). They ‘fixed’ that by a head modification to the coolant flow and it worked better than they planned. It last no time (40k ?) and was discontinued shortly thereafter. I would trust a copperhead before I would GM.

      Anyway Ford, as well as others, ate their lunch. They should have been liquidated rather than bailed out.

      Liked by 1 person

      • Have to agree with you, had a Pontiac Bonneville the engine rolled over and died at about 90K Kilometres, valve train problems. The factory replacement didn’t even do that well, it died at 75K. They were not driven hard and were maintained to the recommended cycles. The car also chewed it’s way through three sets of front suspension ball joint, two sets of rear suspension ball joints, two sets of shocks and five, yes five, pairs of front rotors, I think they made them out of jam jar lids, brake hard a few times and they warped. Also replaced the engine management computer after spending a lot of time doing the “code dance” like Willis, there was no code for a defective input/output on the computer itself, got there using the bush mechanic approach.

        It was by far the worst car I ever owned, I will never buy another GM product. My experience with Chrysler and Ford products has not been much better. I now buy nothing but Acura for both my wife and myself, totally reliable, not one failure of any kind over the last twenty years on five vehicles and likely well north of 500K Kilometres, not even a brake job.


        • Let’s see: Pontiac Fiero overheat because the coolant ports had casting flashing left in them. Olds diesel engine failure because they tried to make a gas engine into a diesel. Chevy Citation: wheels falling off, engine mounts breaking. Chevy Monza (the rebranded Vega) that had to have to engine removed to change the last spark plug. Using a plastic gear that was meant for a compact transmission in a full size V8. Those are just off of the top of my head. And your can read the horror stories about how dysfunctional the Freemont plant was with people drinking on the line.


      • The last new American car I bought was a 1972 Vega GT. At 40,000 miles on the odometer my wife was driving to pick me up at work when it threw a rod through the side of the engine block. According to her, several minutes before it quit it started smoking out the back and making a rattling sound. When the engine finally blew (in front front the guard shack at work) there had been a Houston city police car hiding in the smoke. They had been trying to pull her over for several blocks. She just told them she couldn’t see ’em in the smoke. The guys in the guard shack were laughing pretty hard when they finally called me to come out rescue her. I’ve refused to own another GM ever since.


  20. NC and DaveBurton
    When a new car is manufactured the ECM (Engine Control Module) is preset with the I/M status flags.
    If the battery is disconnected or if any diagnostic trouble codes are cleared then the status flags are cleared.
    They do this so that someone can’t just clear an emissions related trouble code and get their car tested.
    The I/M status flags represent emissions related groups and usually the ECM runs them in order. For example the catalytic converter efficiency test will not run until the O2 sensor tests run as the O2 sensors test the catalytic converter.
    On cold startup (count down timer shows vehicle off more than 5 hours) the ECM will check the coolant temp sensor and the ambient air temp sensor (they must agree within a few degrees of temp to run certain tests and cannot be too cold or too hot) If coolant or ambient are below certain temps then evap tests will not run.
    After startup both O2 sensors should have flat signal output until the O2 heaters warm them up (1st test to verify heaters are working) front and rear (pre and post Cat) O2 should then begin to show swinging voltages (Wide Band sensor should show oxygen pumping current variations)(2nd test O2 function) When the catalytic converter reaches light off temperature (Begins storing and releasing oxygen) then the rear (post cat) O2 sensor signal should slow way down in activity (3rd test conversion efficiency)
    As you drive the system continually monitors the O2 values and feeds back minor adjustments to the fuel air mix while watching that the adjustments are not too large (Plus and minus about 20% max)

    Liked by 1 person

  21. What? No driving with the hatch open on a line12.435 degrees off the alignment of Jupiter and Pluto at 4:37am central time? Oh yeah,that’s to reset the Ford tire pressure monitors… Some of the BMW resets require opening and closing specific doors and trunk, leaving one or two open in a specific order to reset some of the systems. Like the fire drill we did as kids at red lights. Who thinks of these things? Talk about adding mystery to computers…


  22. As a motor mechanic I never liked the involvement of “mootas” in motor vehicles, yes they can be useful in getting the best out of them but they bring a whole host of other issues with them where older vehicles are mechanical (I can fix mechanical) trying to track faults flagged up by a ECU (electronic Control unit) can be a nightmare especially as they are connected to so much else as well and in there desire to save money and weight manufacturers shave everything back as much as they can. Many of the electronic parts have a life expectancy of about 5-7 years which suits their bank balance but not people wanting to keep things for longer than is fashionable a simple poor earth connection can cause all sorts of havoc I was told by trainer for a manufacturer that he could put a fault on a vehicle that would take days or weeks to find a poor connection on the brake light bulbs would cause an engine miss fire that was intermittent but not in time with the brakes being applied!
    I have a 22 year old diesel which has been cheap and easy to maintain and bugs the life out of “eco” nuts so I love it and will keep it going as long as I can.

    James Bull


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